1. Field of the Invention
The invention relates generally to portable containers and more particularly to portable containers wherein the serving temperature of the contents is maintained with a temperature-controlled integrated electric heating element and a battery.
2. Description of the Prior Art
Vacuum bottles and other highly insulated containers operate by slowing down the serving temperature heat loss of foods, beverages, or industrial chemicals. Specialized portable warmers and heaters that will maintain serving temperatures also exist that add heat derived from house current, natural gas, or other combustible fuels. Simple containers alternatively may be placed on hot-plates or other similar cooking devices that will maintain the heat of a container and its contents. Water-filled trays that are filled with hot water prior to serving also extend the time the food in them will remain hot.
The drawbacks of vacuum bottles and highly insulated containers are that they usually include a lid that must be placed back on the container after each use and they all experience a constant temperature decay that commences as soon as the container is initially closed. The temperature of the food and/or beverage contents inside the container start at an appropriate serving temperature, but cool-off considerably by the time the contents are consumed. Removing the lid each time the contents are sampled is also inconvenient.
Specialized portable warmers and heaters usually employ heat energy sources that require house wall current or open flame. These heat sources render these units not truly portable, but rather only transportable. They are also not intended for use as a cup to be raised to the mouth for sipping or use as an individual's dinner plate.
Water-filled trays are inconvenient due to the fact that the water in them must be added hot; the hot water may be initially too hot and thus warm the food and then cool-off to allow the food to become cooler than ideal serving temperature. In addition, the weight of the water added to a water-filled tray makes it heavy and awkward to use.
Simple containers can be placed on hot-plates, or other similar cooking devices, but the heat varies because the temperature of the food and/or beverage is not sensed, and the container must be returned to the heater each time it has been lifted away.